1. Technical Field
The present invention relates to a structure and a method for connecting a shield cable, in which a plurality of wires are covered with a shield lacing, to an electronic unit installed in the vehicle.
Further, the present invention relates to a structure and a method for connecting a plurality of wires to an electronic unit installed in the vehicle in the waterproof condition.
2. Related Art
If the wires must be shielded from other circuits in the situation that the cable is connected electrically to the electronic unit (e.g., the control box of the electric motor) installed in the vehicle, the shield cable is employed as the cable. As the shield cable, the cable in which respective wires are covered with the flexible shield lacing (e.g., copper lacing) is often employed. An example of the method of connecting such shield cable to the electronic unit in the prior art will be explained with reference to FIG. 9 and FIG. 10 hereunder.
1) As shown in FIG. 9, end portions of respective wire 12 are exposed by removing an end portion of the shield lacing 10 by a length L.
2) As shown in FIG. 10, the internal conductors 13 are exposed by stripping off the coating from the end portions of respective wire 12, and then the cylindrical waterproof plugs 14 made of rubber, etc. are fitted at the position located at the back of the exposed portions from the outside. This waterproof plug 14 consists integrally of the press-fitting portion 14a with the small diameter, the main body 14b with the large diameter, and the flange portion 14c with the larger diameter in sequence from the top end side.
3) The terminal tools 16 are fixed to the end portions of respective wires 12. As this terminal tool 16, as shown in FIG. 10, the tool having the ring-like top end portion having the through hole therein, the conductor barrel portion 16b formed on the rear side of the top end portion, and the insulation barrel portion 16c formed on the rear side of the barrel portion is employed. The conductor barrel portion 14b is press-fitted around the internal conductor 13, and the insulation barrel portion 16c is press-fitted around the press-fitting portion 14a of the waterproof plug 14. Also, as shown in FIG. 9, the ring-like terminal tools 16xe2x80x2 is connected/fixed to the end portion of the drain line 15 that is connected to the shield lacing.
4) As shown in FIG. 9, the end portions of respective wires 12 (i.e., the terminal tools 16) are passed through the cylindrical through hole portions 19 provided to the unit housing 18 of the electronic unit, and then the waterproof plugs 14 are press-fitted into the through hole portions 19, whereby the waterproof structure is formed.
5) The terminal tools 16 of respective wires 12 that enter into the unit housing 18 via the through hole portions 19 are connected to the electronic circuit (not shown) housed in the unit housing 18.
6) The vis 22 is passed through the terminal tool 16xe2x80x2 that is fixed to the end portion of the drain line 15, and then this vis 22 is screwed into the screwed hole 20 provided to the outer surface of the unit housing 18, whereby the terminal tool 16xe2x80x2 is brought into contact with the outer surface of the unit housing 18 and fixed thereto. As a result, the shield lacing 10 can be brought into the state that it can be grounded via the drain line 15, the terminal tool 16xe2x80x2, and the outer surface of the unit housing 18.
In the prior art, as the structure for connecting the cable consisting of a plurality of wires to the electronic unit (e.g., the control box of the electric motor) installed in the vehicle in the waterproof condition, the structures shown in FIG. 19 and FIG. 10 are known. The connecting procedures will be given as follows.
1) As shown in FIG. 19, in the shield cable covered with the metal shield lacing 110 having the conductivity, the end portions of respective wires 12 are exposed by removing the end portion of the shield lacing 10 by a length L.
2) As shown in FIG. 10, the internal conductors 13 are exposed by stripping off the coating of the end portions of respective wires 12, and then the cylindrical waterproof plugs 14 made of rubber, or the like are fitted from the outside at the position adjacent directly to the rear side of the exposed conductors 13. This waterproof plug 14 consists integrally of the press-fitting portion 14a with the small-diameter, the main body portion 14b with the large-diameter, and the flange portion 14c with the larger-diameter from its top end side.
3) The terminal tools 16 are fixed to the end portions of respective wires 12. As this terminal tool 16, as shown in FIG. 10, such a tool that has the ring-like top end portion in which the through hole is opened, the conductor barrel portion 16b formed at the rear side of the top end portion, and the insulation barrel portion 16c formed at the rear side of the barrel portion 16b is employed. The conductor barrel portion 16b is fitted around the internal conductor 13 by the compression, and also the insulation barrel portion 16c is fitted around the press-fitting portion 14a of the waterproof plug 14. Also, as shown in FIG. 19, the ring-like terminal tool 16 is connected to the end portion of the drain line 115 connected to the shield lacing 110, and then fixed thereto.
4) As shown in FIG. 19, the end portions of respective wires 12 (i.e., terminal tools 16) are passed through the cylindrical through holes 119 that are provided to the unit housing 118 of the electronic unit, and then the waterproof plugs 14 are press-fitted into the through holes 119, whereby the waterproof structure is constructed into the unit housing 118 via the through holes 119 are connected to the electronic circuit (not shown) housed in the unit housing 118.
6) The vis 122 is passed through the terminal tool 16xe2x80x2 fixed to the end portion of the drain line 15 and then screwed into the screwed hole 120 provided on the outer surface of the unit housing 118. Thus, the terminal tool 16xe2x80x2 is brought into contact with the outer surface of the unit housing 118 and fixed thereto. As a result, the shield lacing 110 can be grounded via the drain line 15, the terminal tool 16xe2x80x2, and the outer surface of the unit housing 118.
In the above structure and method, when the terminal tools 16 are fixed to the end portions of respective wires 12, the end portion of the shield lacing 10 must be removed by the length L in order to expose the end portions of the wires. Therefore, respective wires 12 are not covered with the shield lacing 10 and exposed to the outside in this area of length L, and thus the shielding performance is lowered by such length. Also, in order to ground the shield lacing 10, operations for fixing the grounding terminal tool 16xe2x80x2 to the end portion of the drain line 15 separately from the terminal tools 16 and then fixing the terminal tool 16xe2x80x2 to the outer surface of the unit housing 18 are needed. Such operations are troublesome and also the connection structure becomes complicated.
Further, in the above structure and method, the operation for press-fitting the waterproof plugs 14 fitted to respective wires 12 into the through holes 119 must be carried out wire by wire. In addition, in order to prevent the waterproof plugs 14 from coming off from the through holes 119, the fixing operation must be applied separately after the press-fitting, so that the working efficiency is degraded and also the structure tends to become complicated. Further, the development of the waterproof connector is forwarded as the means for simplifying the above connecting operation. However, often such connector is complicated in structure to cause a higher cost.
The present invention is made in light of such circumstances. It is an object of the present invention to provide a structure and a method capable of assuring the high shield performance in connected portions between a shield cable and an electronic unit with a simple structure.
Further, it is another object of the present invention to achieve effectively a waterproof connection between a plurality of wires and an electronic unit with a simple structure.
As the means for solving the above subjects, the present invention provides an electronic unit and a shield cable connecting structure for connecting wires of a shield cable, in which a plurality of wires are covered with a shield lacing, to circuits in an electronic unit, which comprises terminal tools fixed to end portions of the wires and connected to circuits of the electronic unit; a unit housing at least an outer surface of which is formed of metal, and which houses the circuits of the electronic unit therein and which has through portions through which the end portions of the wires are passed; and a metal shield case fixed to an end portion of the shield lacing to be conductive with the shield lacing, and fixed to the outer surface of the unit housing while covering the wires that are passed through the through portions; wherein the shield case and the shield lacing as well as the outer surface of the housing are grounded in a situation that the shield case is fixed to the outer surface of the housing.
According to this structure, since the connected portions between the wires and the unit housing are covered with the shield case, the high shielding performance can be assured by forming successively a series of shield structures from the shield lacing to the unit housing. Also, since the shield case can be brought into the grounded state only by fixing the shield case to the outer surface of the unit housing, the operation becomes simple.
In this structure, it is preferable that the wire holders which are installed in the shield case to fix relative positions of the wires in the shield case to positions that correspond to relative positions of the through holes in the unit housing should be further comprised. If the relative positions of the wires are fixed by the wire holders, the operation of inserting respective wires into the through portions of the unit housing can be facilitated.
In addition, in the structure in which the waterproof plugs that are interposed between outer peripheral surfaces of the wires and inner peripheral surfaces of the through portions to prevent entering of a moisture are fitted to respective wires, the waterproof plugs can be fixed to the wires by a simple operation if the wire holders sandwich collectively these waterproof plugs from outsides and also respective waterproof plugs are fixed to the waterproof plugs by this sandwich.
Also, the present invention provides the electronic unit and a shield cable connecting method of connecting wires of a shield cable, in which a plurality of wires are covered with a shield lacing, to circuits in an electronic unit, which comprises a step of fixing terminal tools to end portions of the wires while retreating an end portion of the shield lacing from end portions of the wires; a step of fixing a metal shield case to the end portion of the shield lacing; a step of passing the end portions of the wires through through portions provided in a unit housing at least an outer surface of which is formed of metal and which houses the circuits of the electronic unit therein; a step of connecting the terminal tools, that are provided to the end portions of the wires passed through the through portions, to circuits of the electronic unit; and a step of fixing the shield case, that is fixed to the end portion of the shield lacing, to the outer surface of the unit housing so as to bring the shield case into a state that the shield case and the outer surface of the housing are grounded.
According to this method, the terminal tools are fixed to the end portions of the wires in the situation that the wires are exposed by retreating the end portion of the shield lacing once, and then the shield case is fixed to the outer surface of the unit housing to cover the wires with the shield case in the situation that the shield case is fixed to the end portion of the shield lacing. Therefore, the connecting structure having the excellent shielding performance can be constructed by a simple operation without the removal of the shield lacing
As a means for solving the above subjects, the present invention provides an electronic unit and wires waterproof-connecting structure for connecting a plurality of wires to an electronic unit circuit installed in a vehicle in a waterproof condition, which comprises a unit housing for housing circuits of the electronic unit and having through holes through which end portions of respective wires are passed; waterproof plugs fitted to the wires respectively such that the waterproof plugs are interposed between outer peripheral surfaces of the wires and inner peripheral surfaces of the through holes to prevent entering of a moisture into the unit housing; and a coupling member for coupling these waterproof plugs so as to fix relative positions of the waterproof plugs to positions that correspond to relative positions of the through holes in the unit housing; wherein the waterproof plugs are fitted into the through holes while inserting respective wires into the through holes in a situation that the waterproof plugs are coupled mutually by the coupling member, and the coupling member is fixed to an outer surface of the unit housing.
Also, the present invention provides an electronic unit and wires waterproof-connecting method of connecting a plurality of wires to an electronic unit circuit installed in a vehicle in a waterproof condition, which comprises the steps of fixing relative positions of waterproof plugs to positions that correspond to relative positions of the through holes, that are provided in a unit housing which houses circuits of the electronic unit, by coupling mutually the waterproof plugs, that are fitted to the wires respectively, via the coupling member; fitting the waterproof plugs into the through holes while passing end portions of respective wires through the through holes under above condition; and fixing the coupling member to an outer surface of the unit housing.
According to the above structure and method, since the waterproof plugs fitted to respective wires are coupled by the coupling member (e.g., respective waterproof plugs are held commonly by the common coupling member), the fitting operation of respective waterproof plugs into the through holes in the unit housing can be carried out in the gross with maintaining this coupled state. In addition, the disconnection prevention of the waterproof plugs from the through holes can be collectively attained only by fixing the coupling member to the outer surface of the unit housing together with the fitting operation, and the waterproof structure can be constructed effectively with a simple structure.
It is preferable that, if the influence of the noise upon respective wires or the influence of the noise of the wires upon the outside must be taken into consideration, the shield cable in which the plurality of wires are covered with conductive shield member should be employed. In this case, as the means for grounding the shield member, for example, the terminal tool and the waterproof plug may be installed onto the drain line that is extended from the shield member in the same way as respective wires, then the waterproof plug as well as other waterproof plugs may be fitted into the through hole of the unit housing while holding it by the coupling member, and then the terminal tool may be connected to the earth circuit of the electronic unit. In this case, if the coupling member can be fixed to the unit housing by providing the bolt through holes in the coupling member and fixing the bolts to the unit housing side in the condition that the metal bolts are passed through the bolt through holes and also the shield member can be grounded via the bolts and the unit housing, the shield member can be grounded (i.e., the shield structure can be constructed) without the terminal tools and the waterproof plugs by utilizing the bolts and the unit housing per se as the connecting members.
In order to connect electrically the shield member and the metal bolts, for example, the drain line extended from the shield member may be directly connected to the bolt. In this case, if the shield member can be fixed to the coupling member by connecting the fitting tools having the bolt through holes to the shield member and fixing the bolts to the unit housing side in the state that the metal bolts are passed through these bolt through holes and the bolt through holes of the coupling member and also the shield member can be grounded via the fitting tools, the bolts, and the unit housing, the shield member can be fixed to the coupling member and the unit housing by the bolts and also the electrical connection between the bolts and the shield member can be accomplished via the fitting tools. Thus, the operation efficiency can be further enhanced. Also, since the exposed length of the wires (the length of the portion of the wire that is not covered with the shield member; the length L in FIG. 19) can be very reduced, the shielding performance can be improved.